Sunburn preventive



Patented Nov. 16,

I UNITED i STATE- seminar: ranvnmrrvr:

John liflglaresc, Cincinnati, Ohio, assignor to The National Marking Machine Company, Cincinnati, Ohio, a corporation oi Ohio No Drawing. Application tune at. rear,

Serial No. eraser There are on the market several sunburn preventives, generally called sun tan lotions, which contain an ingredient having the characteristic of absorbing the shorter wave lengths of the solar rays generally described as ultraviolet rays or rays having a wave length of from 3000 to 3600 Angstrom units and converting them to wave lengths greater than 4000 Angstrom units which will not burn or'injuriously affect the human skin and which will not decolorize human hair. Said ingredient, which may be termedthe vitalizing ingredient, is usually carried in a vehicle of greasy nature, such, for illustration, as petroleum jelly, and this is applied to the portions of the human skin and hair which it is desired to protect. With such sun tan lotions the vitalizing ingredient is readily and easily washed or rubbed ofi with the vehicle, and when the vehicle is thus removed all protection against sunburn goes with it. Fur- .thermore, with such sun tan lotions the lotion.

must be applied to the skin in a relatively thick layer which is clearly visible and, therefore, objectionably unsightly.

My object is to provide a sunburn preventive in which the vitalizing ingredient has an nity for human skin and hair and which, when carried in a suitable vehicle and applied to the skin and hair will adhere to the skin and hair after the vehicle has been removed, in a manner simi= lar to that of a basic dyestuff applied to silk or wool, and which cannot be washed or rubbed oh, and, therefore, will protect the user from the injurious effects of direct sunlight for a relatively long time.

A further object is to provide a sunburn preventive which is substantially colorless and which, when applied to human skin and hair, and after the vehicle has been removed, will be in such a thin layer and colorless to such a degree that it is not clearly visible or of such greasy nature as to detract from the appearance of the user.

My improved vitalizing element has flve important characteristics: I

1. It is highly fluorescent in ultraviolet light or light rays. of wave lengths from 3000 to 3600 Angstrom units. This indicates a high absorption I in this region;

2. It is light in color and, therefore, substanskin and hair opaque to ultraviolet light even after removal of the vehicle.

My vitalizing ingredients may be described chemically as heterocyclic, aromatic, light col- 5 cred, fluorescent. basic compounds, I

' It is recognized that there are two essential parts of a fluorescent molecule; first the lumino- 'phore," which in this case is the heterocyclic and aromatic rings; and second the fluorophore,

which in this case is a basic auxochromic group.

It is known that it is not necessary to have either a heterocyclic ring, or a basic auxochrome in order to have fluorescence, for it is possible to have an aromatic ring for the luminophore, and ceraromatic ring, for the auxochrome.

I have obtained satisfactory results with the following formulae for thevitalizing ingredient. The numbering oi positions is in accord with Chemical Abstracts, vol. 31 on.

.i-ethyl 3-dimethylamino carbazole amino group gives the molecule an amnity for human skin and hair.

4-methyl 7-diethylamino coumarine The coumarine nucleus is the luminophore and the diethylamino group is the auxochrome pro moting fluorescence and causing aiflnity for skin and hair.

o 3-methyl b' -dimethylamzno azimidobenzene 0&1: N

The methyl-azimidobenzene nucleus is the luminophore, the dimethylamino groupis the auxochrome promoting fluorescence and giving 00 an aflinityfor skin and hair.

tain other unsaturated groups, such as another In adz-(para amino phenyl) -amino benzimidazole Here there are actually three auxochromes, the 2.-phenyl,' the para amino and the 5-amino groups. The phenyl group promotes only weak fluorescence, but the para-amino and 5-amino groups give a much stronger fluorescence and give an afllnity for skin "and hair.

z-phenul 5-amino benzoxazqle' Z-(pam amino phenyl) (i-methyl benzthiazole (commonly called dehydrothic-para-toluidine) CH3\ S\ I The benzthiazole is the luminophore. Here there are two auxochromes, the 2-phenyl and the paraamino groups. The phenyl gives only a weak fluorescence, the para-amino gives a much stronger fluorescence and gives the compound an amnity for skin and hair.

S-dimethylamino acridine Here the luminophore is the pyridine and unsubstituted benzene ring. The other benzene ring and dimethylamino group are the auxochromes. The benzene ring gives only a faint fluorescence, the dimethylamino group gives a strong fluorescence and in addition gives the molecule an affinity for skin and hair.

It is to be noted that each of the above mentioned compounds includes an amino or a substituted amino group, and that appears to be a characteristic which isessential to render a fluorescent dyestufi useful in my present invention.

The first three desired properties, namely fluorescence under ultraviolet light of wave length 3000 to 3600 Angstrom units, substantial lack of 60 color, and solubility in suitable solvents, may be rapidly and easily checked. The fourth, nontoxicity to human skin, requires the usual biological methods of testing. The fifth, afilnity for the human skin and hair, may be examined by testing the ailinity the compound has for protein fibers, namely silk and wool. Merely immerse the piece of silk or wool in an aqueous or alcoholic solution of the compound and wash and rinse thoroughly in warm water. Then examine the piece of silk or wool under an ultraviolet light, such as the General Electric H4 Black Bulb, in the substantial absence of visible light. A strong fluorescence shows the compound has an affinity for these protein fibers and has an aiilnity for human skin and hair. The aiiinity for skin and hair is not as great as is the afllnity for silk and wool, probably the skin is living matter. In the for human skin and hair by the expression "substantive to human skin and hair." By that, I mean that the fluorescent compound, although colorless, reacts with or is absorbed in human skin and hair, without the after the mannerof a substantive dye.

My compounds are all definite chemical compounds with definite solubilities and other properties. These compounds are intrinsically fluorescent and therefore do not require the addition of extraneous substances, such as acids or bases, to promote fluorescence. For example the naphthol sulfonic acids will not fiuoresce in a medium of pH less than 9, and quinine sulfate will not fiuoresce in a medium of pH more than 5. Both of these extreme values would irritate tender skin.

My compounds may be applied, either in the form of a solution, such as a mixture of ethanol, water and glycerol; dissolved or dispersed into a paste with such vehicles as vanishing cream or Carbowax"; or merely diluted with some inert powder, such as talcum powder or zinc stearate, and dusted on the skin and hair.

In whatever manner the essential ingredients be carried, the method of application is the same. The composition is rubbed on the skin or hair and allowed to remain on for at least flve minutes. The fluorescent compound afilxes itself to the skin or hair in much the same manner that a colored dyestufl afllxes itself to textile fibers from a dye bath. The vehicle is then washed or rubbed off. The amount that remains on affixed to the skin or hair is sufficient to give protection against harmful ultraviolet rays for a period of twenty-four hours.

follows A. Into 100 mls. of a mixture of 70 parts ethanol, 25 parts water, and 5 parts glycerol by volume, dissolve 3 grams of any one of the said vitalizing ingredients;

B. Into 100 grams of vanishing cream, thoroughly grind or incorporate 3 grams of any one of the said vitalizing ingredients;

C. Into 100 grams oi. Carbowax, a water soluble synthetic wax obtainable from Carbide and Carbon Chemical Corporation, thoroughly grind or incorporate 3 grams of any one 01 the said vitalizing ingredients.

55 D. Into 100 grams of talcum powder, or zinc stearate, thoroughly incorporate 5 grams of any one of the said vitalizing ingredients.

In practice I have dissolved or dispersed, or ground into or incorporated into the various vehicles mentioned, a small quantity of the various vitalizing ingredients mentioned, and forming a paste. I have rubbed this on the skin and hair to be protected, and permitted it to remain in such condition for about five minutes; during that time I have found that a sufflcient quantity of the vitalizing ingredient has, by reason of its afllnity to the skin and hair, become aifixed thereto. I have then washed or rubbed substantially all of the vehicle from the skin and hair. The remaining vitalizing element on the skin and hair was in such a thin layer and being substantially colorless was not objectionably visible and did not detract from the appearance of the person to which it was applied. I have demonspecification and claims I 5 I have referred 'to this characteristic of -afllnity use of any mordant,

My preferred compositions of matter are as 2,334,343 strated that with persons more than usually sus- .vitalizing ingredient becomes affixed to human skin and hair somewhat in the manner of basic dyestuffs adherence to silk or wool, that it will remain on the skin and hair only for a period of about 24 hours, after which it is removable by bathing or rubbing, or in some manner it disappears. This is probably due to the fact that the living tissues to which it is applied function to remove it. A fresh application of my sunburn preventive was applied each day for several days of exposure, and finally the sun tan became sumciently intense to substantially protect the person from sunburn.

My improved method of applying sunburn preventive to the human skin and hair is as follows:

The vitalizing ingredient is dispersed'in a vehicle of a non-greasy character and readily removable, or in a powder such as ordinary face powder which will adhere to the skin and hair. This is applied to the skin and hair in the ordinary manner and permitted to remain for a short time. I have had satisfactory results by permitting it to remain for fivevminutes. During that time a suflicient amount of the vitalizing ingreclient for sunburn prevention separates from the vehicle and'adheres to the skin and hair, due to its afiinity for the skin and hair. Then the vehicle and other ingredients contained therein are washed orrubbed ofl, with the result that only a microscopic layer of the vitalizing ingredient remains, and since that is substantially colorless, it is not objectionably visible and does not detract from the appearance of the user.

I claim as my invention:

1. A sunburn preventive to be applied as a coating to human skin and hair for the purpose of rendering the outer surfaces thereof, after removal of the coating, opaque to ultraviolet light comprising a non-toxic carrier having dispersed therein a colorless, fluorescent, basic compound, substantive to human skin and hair, selected from the group consisting of Q-ethyl 3-dimethylamino CHa carbazole CHI z-(para amino phony!) S-amtno benzimiduzole z-phenyl S-amino benzomazole z-(pam amino phenyl) 6-methzil benzthiazole s-dimethylamino acridine 3. A sunburn preventive to be applied as a coating to human skin and hair for the purposeof rendering the outer surfaces thereof opaque to ultraviolet light, after removal of the coating, comprising a suitable carrier having dispersed therein the compound, 4-methy1 7-diethylamino coumarine, having the following structural formula:

some n: 

